Liquid supply mechanism and printing device

Abstract

An ink supply mechanism ( 50 ) provided with: a main tank ( 60 ); a sub-tank ( 70 ) for storing ink supplied from the main tank ( 60 ) and supplying the ink to an ink jet head ( 2 ); a first communication passage ( 52 ) one end of which communicates into the ink in the main tank ( 60 ) and the other end of which communicates into the ink in the sub-tank ( 70 ); and a second communication passage ( 53 ) one end of which communicates into the main tank ( 60 ) and the other end of which communicates with a position in the sub-tank ( 70 ) higher than the other end of the first communication passage ( 52 ), and part of which is disposed at a position higher than the liquid level of the ink in the main tank ( 60 ).

The invention claimed is: 
     
       1. A printing device, comprising:
 a liquid supply mechanism comprising:
 a main tank that is sealed and stores a printing liquid, 
 a sub-tank which is disposed below the main tank, an inside of the sub-tank contacting outside air, the sub-tank storing the printing liquid supplied from the main tank and supplying the stored printing liquid to a printing portion, the printing portion being disposed at a position higher than a liquid surface of the printing liquid in the sub-tank, and the printing portion being supplied with the printing liquid from the sub-tank of the liquid supply mechanism to apply printing to a print medium, 
 a first communication passage whose one end extends into the printing liquid in the main tank and whose other end extends into the printing liquid in the sub-tank, and
 a second communication passage one end of which extends into the main tank, an other end of which extends to a position as high as or higher than the other end of the first communication passage in the sub-tank, and a portion of which is disposed at a position higher than an uppermost position of a liquid surface of the printing liquid in the main tank, wherein 
 
 in the main tank, a cylindrical member and a lid member, which is provided with respective connection apertures for the first communication passage and the second communication passage, are screwed to each other, wherein a sealed space for storing the printing liquid is formed; 
 
 a supply passage whose one end extends into the printing liquid in the sub-tank and whose other end communicates with the printing portion, wherein
 the printing liquid in the sub-tank is supplied through the supply passage by capillarity in the printing portion. 
 
 
     
     
       2. The printing device according to  claim 1 ,
 wherein the connection apertures, the one end of the first communication passage, and the one end of the second communication passage have each a joint that curbs an outflow of the printing liquid and is mountable/demountable. 
 
     
     
       3. The liquid supply mechanism according to  claim 2 , wherein
 the lid member has a lid main body that has an asymmetric shape when seen in an axis direction of the cylindrical member. 
 
     
     
       4. The printing device according to  claim 1 , comprising:
 a plurality of the printing portions that perform printing by using printing liquids that have colors different from one another, and 
 a plurality of the liquid supply mechanisms that supply a printing liquid corresponding to each of the printing portions, wherein 
 the plurality of the printing portions being fixedly disposed successively in a conveyance direction of the print medium. 
 
     
     
       5. A printing device, comprising:
 a liquid supply mechanism comprising:
 a main tank that is sealed and stores a printing liquid, 
 a sub-tank which is disposed below the main tank, an inside of the sub-tank contacting outside air, the sub-tank storing the printing liquid supplied from the main tank and supplying the stored printing liquid to a printing portion, the printing portion being supplied with the printing liquid from the sub-tank of the liquid supply mechanism to apply printing to a print medium, 
 a first communication passage whose one end extends into the printing liquid in the main tank and whose other end extends into the printing liquid in the sub-tank, and 
 a second communication passage one end of which extends into the main tank, other end of which extends to a position as high as or higher than the other end of the first communication passage in the sub-tank, and a portion of which is disposed at a position higher than an uppermost position of a liquid surface of the printing liquid in the main tank, wherein 
 in the main tank, a cylindrical member and a lid member, which is provided with respective connection apertures for the first communication passage and the second communication passage, are screwed to each other, whereby a sealed space for storing the printing liquid is formed, and 
 wherein the main tank is provided with a partition member that partitions an inside of the main tank into a storing portion of the printing liquid and an air portion, and moves in accordance with reduction in the printing liquid of the storing portion; 
 a supply passage whose one end extends into the printing liquid in the sub-tank and whose other end communicates with the printing portion, wherein 
 the printing liquid in the sub-tank being supplied through the supply passage by capillarity in the printing portion. 
 
 
     
     
       6. The liquid supply mechanism according to  claim 5 , wherein
 the partition member is a liquid bag that is housed in the main tank, has flexibility, and is filled with the printing liquid. 
 
     
     
       7. The liquid supply mechanism according to  claim 5 , wherein the connection apertures, the one end of the first communication passage, and the one end of the second communication passage have each a joint that curbs an outflow of the printing liquid and is mountable/demountable. 
     
     
       8. The liquid supply mechanism according to  claim 7 , wherein
 the lid member has a lid main body that has an asymmetric shape when seen in an axis direction of the cylindrical member. 
 
     
     
       9. The printing device according to  claim 7 , comprising:
 a plurality of the printing portions that perform printing by using printing liquids that have colors different from one another, and 
 a plurality of the liquid supply mechanisms that supply a printing liquid corresponding to each of the printing portions, wherein 
 the plurality of the printing portions being fixedly disposed successively in a conveyance direction of the print medium.